unified: move basic ticks-to-ms conversion to kernel.h

The basic conversion, i.e. not handling the TICKS_UNLIMITED case, is
useful internally since the kernel is still tick-based.

Change-Id: I00a01047ec48dad6834dd8ea5dc831eb8c0c2501
Signed-off-by: Benjamin Walsh <benjamin.walsh@windriver.com>
2 files changed